Flame arrester



Oct. 20, 1970 v v E, B. WAGNER 3,535,066

FLAME ARRESTER Filed Aug. 26, 1968 2 Sheets-Sheet 1 lllHlll JNVENTOR. EDDIE B. WAGNER Oct. 20, 1970 E. B. WAGNER 3,535,066

FLAME ARRESTER Filed Aug. 26, 1968 2 Sheets-Sheet 2 INVENTOR.

EDDIE B. WAGNER BY n United States Patent Oifice 3,535,066 FLAME ARRESTER Eddie B. Wagner, Portland, reg., assignor to Wagner Mining Scoop, Inc., Portland, Oreg., a corporation of Oregon Filed Aug. 26, 1968, Ser. No. 755,188 Int. Cl. F23d 13/46 US. Cl. 431-346 4 Claims ABSTRACT OF THE DISCLOSURE A flame arrester for the air intake of an internal combustion engine. A cylindrical housing contains a coil Wound from two strips of metal, one corrugated and one flat, forming narrow axial air passages. The housing is made of separable parts for removal of the coil for cleaning. One housing part contains a butterfly valve to shut off the air supply to the engine. The valve is spring closed and normally held open by an air cylinder which is part of a safety system for the engine.

BACKGROUND OF THE INVENTION This invention relates to a flame arrester for the intake of an internal combustion engine.

It is necessary in mining work and other applications to provide a flame arrester to prevent explosion hazard from the backfiring of the engine through its air intake. Flame arresters for this purpose have heretofore been excessively heavy and bulky, expensive to manufacture and difficult to clean. They must be taken apart and cleaned periodically to keep the multitude of minute air passages free and unobstructed by dirt and other material which may lodge therein.

As an additional safety feature, it is also necessary in mine work to provide a valve in the air intake which will close automatically and stop the engine instantly in the event of overheating. For the sake of reliability and certainty of operation in an emergency, it is desirable to make such safety devices as simple and trouble free as possible. It is also desirable that they be as small and compact as possible in view of the number of other accessory devices necessary on the engine and it is desirable that they not add excessively to the cost of the equipment.

SUMMARY OF THE INVENTION The present flame arrester is built as a unit which includes an emergency air shutoff valve. This unit is arranged for connection between the intake manifold and the air cleaner. A plurality of housing parts are bolted together for convenient removal of the flame arrester element for cleaning. The flame arrester element itself comprises a transversely corrugated strip of stainless steel and a flat strip. These two strips are coiled about a central spud which provides means for lifting the element out of the main housing part in a convenient manner.

One of the housing parts contains a butterfly valve to shut off the air supply. The valve is normally held open against spring tension by an air cylinder.

Objects of the invention are, therefore, to provide an improved flame arrester for internal combustion engines, to provide a flame arrester and shutoff valve incorporated in a unitary assembly and to provide a compact and economical form of construction which is easy to take apart for cleaning.

The invention will be better understood and the foregoing and other objects and advantages will become apparent from the following description of the preferred embodiment illustrated in the accompanying drawings. Various changes may be made in the details of construction and arrangement of parts and certain features may Patented Oct. 20, 1970 be used without others. All such modifications within the scope of the appended claims are included in the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a flame arrester and air shutoff valve incorporating the principles of the invention;

FIG. 2 is a view on the line 22 in FIG. 1;

FIG. 3 is an exploded view of the device; and

FIG. 4 is a greatly enlarged fragmentary view of the flame arrester coil.

DESCRIPTION OF THE PREFERRED EMBODIMENT Cylindrical main housing 10 includes as an integral part thereof a reducer section 11 having an end flange 12 with tapped holes 13 whereby the housing is mounted on the flanged end of intake pipe 15 by means of bolts 16. Pipe 15 is connected with the intake manifold of the engine, the direction of air flow being indicated by the arrows 16 in FIG. 2. A cylindrical flange cover 17 is secured to the front end of housing 10 by cap screws 18. Flange cover 17 includes as an integral part thereof an annular front plate 19.

A valve unit 20 is mounted on flange cover 17. Valve 20 comprises a housing 21 containing a butterfly valve 22 mounted on a shaft 23. A circular flange end plate 25 having bolt holes around its periphery is welded to a connector tube 26. Tube 26 is Welded or slipped into the intake pipe 30 leading from the air cleaner. Cap screws 31 in flange cover 17 clamp the valve housing 21 between flange plate 25 and front plate 19. Washers 32 are provided in the two joints on opposite sides of valve body 21.

Butterfly valve 22 is normally held open by air pressure in the head end of a single acting air cylinder 35. Cylinder 35 is pivotally mounted at 36 on a supporting bracket 37. A piston rod 38 in cylinder 35 is pivotally connected to a pin 39 in an arm 40 on the end of shaft 23. Upon failure of air pressure in cylinder 35, the butterfly valve 22 is closed by a tension spring 41 connected between bracket 37 and pin 39. The apparatus is used on an engine having an air pressure safety system which normally maintains air pressure in cylinder 35. Upon overheating of the engine, the air safety system exhausts down to atmospheric pressure allowing spring 41 to close the valve, stopping the engine.

The flame arrester unit is indicated generally at 45. This unit is incorporated in a cylindrical shell 46 which fits within housing 10 and seats on a shoulder 47 in the housing. The unit is held in this position by flange cover 17. In the center of the unit is an axial spud 50 having a hole 51 for lifting the unit out of the housing 10 when flange cover 17 is removed.

As shown in FIG. 4, the functional part of unit comprises a flat strip of stainless steel 52 welded at intervals to a transversely corrugated strip 53. After the tWo strips have been welded together, one end of the composite strip is welded to an enlargement 54 on spud and then the composite strip is wound upon itself until it reaches a diameter to fill the shell 46. This provides a multitude of axial openings 55 which are narrow in a radial direction. Air for the engine passes freely through these openings but the narrowness of the openings prevents the passage of flame when the engine backfires.

The coiled strips 52, 53 are retained in shell 46 by a front spider and a back spider 61. Back spider 61 comprises four radial bars welded between an inner ring 62 and a flanged end on shell 46. Front spider 60 comprises four radial bars welded between an inner ring 63 and an outer ring 64. Outer ring 64 is welded to shell 46.

3 Inner rings 62 and 63 seat against the shoulders formed by enlarged portion 54 of spud 50.

In order to clean the flame arrester unit 45 and inspect the valve unit 20, the cap screws 16 and 31 are removed, disconnecting the two units from each other and from the pipes 15 and 30. Removal of cap screws 18 then separates flange cover 17 from housing 10, allowing flame arrester unit 45 to be lifted out of the housing by spud 50. Clamp 70 provides a convenient detachable mounting for the housing assembly.

Having now described my invention and in what manner the same may be used, what I claim as new and desire to protect by Letters Patent is:

1. A safety device for the air intake of an internal combustion engine comprising a plurality of circular housing sections detachably secured together in end to end relation in axial alignment for substantially straight line flow of air through said sections, said section comprising in sequence from the inlet end to the outlet end of the device a flange end plate having an inlet connector tube, a valve housing containing a butterfly valve, a flange cover, and a flame arrester housing having a flanged outlet end for connection with the air intake pipe of the engine; axial cap screws through said flange end plate having threaded engagement with said flange cover and clamping said valve housing therebetween, and axial cap screws securing said flange cover to the inlet end of said flame arrester housing; a flame arrester in said flame arrester housing seated against an annular internal shoulder therein and retained by said flange cover, and an axial spud projecting in an upstream direction from the center of said flame arrester for lifting the flame arrester out of said housing when said housing is separated from said flange cover by removal of said last mentioned cap screws.

2. A device as defined in claim 1 including a spring for closing said valve, and a pneumatic cylinder arranged to hold said valve open against the tension of said spring.

3. A device as defined in claim 1, said flame arrester comprising a cylindrical shell seated on said shoulder, a coil of flat and corrugated strips in said shell, said axial spud being in the center of said coil, and radial spokes on opposite sides of said coil extending between said spud and said shell.

4. A device as defined in claim 1, said flame arrester comprising a cylindrical shell having an inwardly directed flange on one end thereof, a coil of flat and corrugated strips in said shell, said axial spud being in the center of said coil and having shoulders on opposite sides of said coil, a pair of inner rings on said spud seated against said shoulders, radial spokes welded between said flange and one of said rings on one side of said coil, an outer ring welded to said shell on the opposite side of said coil, and radial spokes welded between said outer ring and the other of said inner rings.

References Cited UNITED STATES PATENTS 1,358,812 11/1920 Anderson 123-103 2,403,188 7/1946 McCallum 431-346 X 2,420,599 5/1947 Iurs 48-192 2,913,320 11/1959 Williams 48-192 2,613,144 10/1952 Carnahan 48-192 CARROLL B. DORITY, JR., Primary Examiner US. Cl. X.R. 48-192 

